Figure 1.
Simplified schematic lateral and dorsal skull views of A. Sphenodon (redrawn [87]), B. Crocodylus siamensis (original drawing), C. Allosaurus fragilis (redrawn [92]). All skulls are scaled to the same length. af – antorbital fenestra; ltf – lower temporal fenestra; n – nasal opening; orb – orbital opening; utf – upper temporal fenestra.
Figure 2.
A. Multibody computer model used to calculate the muscle, joint and biting forces for a series of biting simulations. Black arrows represent the location and direction of the fascial force vectors applied to the finite element model over one temporal opening. B. Bite locations. Bilateral (biting on both sides simultaneously) and unilateral biting (biting on one side only) at locations 2–5; bilateral biting only at location 1; ripping bites at location 2 only. Skull measures approximately 68 mm long from the tip of the premaxilla to the posterior end of the quadrate condyles.
Table 1.
The 15 load cases simulated during the MDA and applied in the FEA.
Table 2.
Bite forces and jaw joint forces predicted by the MDA.
Table 3.
Total muscle forces applied to each side of the skull during the MDA.
Figure 3.
von Mises FEA plots during two single bites.
Deformation and von Mises strain plots of the skull of Sphenodon during A. right unilateral biting and B. during bilateral biting on the anterior-most chisel-like teeth; (note the displacements are scaled by a factor of 50).
Figure 4.
Plot of dominant strain regions.
Cumulative map of peak dominant strains over all bites. Red represents regions of the skull where tensile strains are in excess of compressive strains (i.e. tensile strains are dominant), and blue represents regions where compressive strains are in excess of tensile strains (i.e. compressive strains are dominant).
Figure 5.
Models showing which bite location generated the highest strains in particular areas of the skull.
Results based on von Mises strains. A. Unilateral bites and B. bilateral bites. (For example, in A. unilateral biting at location 2 was responsible for the highest strains in those areas coloured blue).
Figure 6.
von Mises element strain distribution plots.
Plot represents the number of elements within the finite element model that experience a specific strain magnitude. The plot shows the element strains from all fifteen biting simulations (labelled individual bites) and the combined loading model.
Figure 7.
Combined loading tensile, compressive, and von Mises strain plots.
Peak combined loading A. tensile, B. compressive, and C. von Mises strain plots.
Figure 8.
von Mises FEA plots with and without fascia forces.
Posterior views of the skull showing von Mises strains predicted by the combined loading model. A. Without including fascial forces and B. including modelled fascial forces (see Figure 2A). Encircled regions highlight areas where strains have changed significantly due to the inclusion of the fascial forces.